pstrName is a text string that describes the event, used only when debugging enabled, to show output on serial portpTest, is a pointer to a test function, prototype: bool (*pTest)(clsEvent* pEvent)pCallback, is a pointer to a function to call when the result of pTest is true, prototype: void (*pCallback)(clsEvent* pEvent)pData, is an option pointer to your own data structure that you can reference via the pEvent pointer passed to your callback.

I am using this to register a test for a push button, the test routine debounces the button and returns true or false, my call back routine then performs an action.